Myxomycetes in Brazilian mangroves: species associated with Avicennia nitida, Laguncularia racemosa and Rhizophora mangle

Mangroves are distributed among tropical and subtropical coastlines of all oceans, and associated macroflora and macrofauna are generally well studied. However, information on mangrove-associated microbiota is still scarce. To help fill this gap in knowledge, we conducted research on the occurrence of Myxomycetes in the southern coast of Pernambuco state, northeastern Brazil. In the Rio Formoso estuary, we examined adult Rhizophora mangle (Rm), Laguncularia racemosa (Lr) and Avicennia nitida (An), collecting samples of live trunk bark (Bk), twigs from aerial litter (Tg), and aerial leaf litter (Lf) for moist chamber culture (n = 600). The following species were identified: Arcyria cinerea (Rm/Tg); A. pomiformis (Rm;Lr/Bk); Collaria arcyrionema (Rm/B); Clastoderma debaryanum (Lr/Bk; Rm/Tg); Cribraria violacea (Rm/Bk;Tg); Physarum auriscalpium (Rm/Tg); P. tenerum (Rm/Bk); Stemonitis fusca (Lr/Tg); S. herbatica (Rm/Lf); S. virginiensis (Rm/Tg) and Stemonaria irregularis (An/Lf). The percentage of positive cultures was very low (24 %), with Rm as the predominant substrate with eight species and Tg as the predominant microhabitat. The majority of species are rare (60 %) and Physarum auriscalpium was the only species frequently registered. The taxonomic diversity indices ranged from 1.00 (Lf;Bk) to 1.20 (Tg). There was no similarity in the composition of myxobiota found on the substrates and microhabitats analyzed. Only S. irregularis was found in mangroves that inhabit areas of higher salinity. Physarum tenerum is reported here for the first time in the mangrove environment.